Perovskite Phase Stabilization of Pb(Zn1\3Ta2\3)O3 Ceramics Induced by PbTiO3 Seeds

In this work a new methodology to stabilize the perovskite phase in (1 - x)Pb(Zn1\3Ta2\3)O3-xPbTiO3 ((1 - x)PZTa-xPT) (x = 0.00-0.80) ceramics is presented. This approach combines the maximization of the crystalo-chemical and thermodynamics requirements and the optimization of the kinetics of the reaction of the perovskite phase formation by using a highly reactive PT nucleus. At the same time, and for comparison, PZTa-PT ceramics are prepared through a conventional mixed oxide procedure (columbite method). The effect of PT seeds is evaluated on the formation of the perovskite phase, and the microstructure and dielectric properties of PZTa-PT ceramics. Analysis of the phase formation process by DTA and XRD shows that PT seeds promote perovskite formation in the Pb (Zn1\3Ta2\3)O3 system at a lower temperature and a lower PT content. A pure perovskite phase is obtained at x = 0.60 by the PT seeds method and only at x = 0.75 by the mixed oxide method. Dense and homogeneous microstructures are observed for seeded ceramics. The dielectric permittivity maximum of 0.40PZTa-0.60PT seeded ceramics is 13 800, compared with 5800 for the ceramics prepared by the conventional columbite method.